Crank case ventilator



Jan. 23, 1934. w (5555 CRANK CASE VENTILATOR Filed July 50, 1927Patented Jan. 23, 1934 UNITED STATES 1,944,341 CRANK CASE VENTILATORWalter A. Geise, Flint, Mich, assignor'to General Motors Corporation,Detroit, Mich., a corporation of Delaware Application July 30, 1927.Serial No. 209,491

5 Claims.

The invention relates to crankcase ventilators for automobile engines.

The object of the invention is to provide a new method and a new devicefor ventilating the engine crank case. More specifically the object isto make use of the forward motion of an auto.- motive vehicle includinga hood, and the consequent air-collecting action of. the hood, todevelop an excess pressure necessary to force the air thru the crankcase. A further object is to provide a simple device which is capable ofadequately ventilating the crankcase by the above method. A furtherobject is to simplify and reduce the number of parts necessary foreificient crankcase ventilation, thus reducing the cost and lesseningthe probability of loose or broken parts and their accompanying noises.A further object is to provide a simple adjustment by means of which dueallowance can be made for varying temperatures at which it is necessaryfor machine to operate, thus insuring adequate ventilation at alltemperatures.

Other objects and advantages of the invention will appear in the courseof the following description, taken in connection with the accompanyingdrawing, and will be particularly pointed out in the appended claims.

In the drawing:

Figure 1 is a side elevation with part of the hood broken away, showinga conventional internal combustion engine with two air inlet openingsand the outlet conduit on the opposite side of the hood shown in dottedlines.

Figure 2 is a view of the structure shown in Figure 1, partly intransverse section.

Figure 3 is a section on the line 33 of Figure 1, showing the inlet indetail, with the lower part broken away.

In prior constructions, it has been customary to provide a suction oraspirating device on the outlet conduit and thus, by providing inletopenings ventilate the crankcase by suction. In order to do away withthe disadvantages which accompany this system, I have devised thepresent method.

I have found that in a car in which the engine compartment is closed onthe under side, the air pressure within the hood can be increasedconsiderably above atmospheric pressure by partly closing the louvers ordoing away with them entirely. In order to make use of this pressure inventilating, restricting and controlling the egress of air from the hoodI have provided one or more inlet openings in the crankcase within thehood space and an outlet which must extend outside the hood space or toa region of atmospheric presl 7 sure. In the conventional engine asillustrated, I have not shown any fan to force the air toward thev rearpart of the engine because I wish it to be understood that my novelmethod of ventilation can be used on a car even without such a fan. Theforward movement of the car may be used to cause an, increase in arestricted-exit pressure within the hood sufliciently great'to force acurrent of air thru the inlet into the crankcase and out thruthe outletprovided.

In the drawing, the numeral 1 indicates generally the hood of anautomobile. The hood is formed in the present case without the customarylouvers, tho it is within the scope of my invention to provide louversof less than the ordinary l That is, the hood is substantially entirelyclosed except for the radiator or like inlet openings, the louvers orsimilar outlet openingswhich may be provided as indicated above, and theventilating passage through the crank case. In the following descriptionand claims, the terms closed hood controlled-exit hood are usedto denotea hood formed so that, by one of these means, the air pressure about theinlet opening may be maintained above that of the atmosphere. The engineis of the ordinary vertical type, the numeral 4 indicating the jacketedcylinder, 5 the piston, 6 the connecting rod, '7 the crankshaft and 8the crankcase. The numeral 10 indicates generally an inlet opening andthe numeral 11 an intermediate portion of a special outlet fitting. Inthe present case, I have shown two inlet openings and one outletopening, tho it is obvious that this number may be varied to suit therequirements of diiferent engines.

As shown in Figure 3, the air inlet comprises a cylindrical part 15,fixed in a correspondingly shaped opening 16 in the crankcase. Fixed inthe side of the cylinder 15, as at 17, is a screw or lug extendingwithin the cylinder. Fitting snugly within the cylinder 15 and slidabletherein is the cylinder 19, and fixed rigidly to the cylinder 19, as bya bolt 20, is the cap 21. At its upper end, the cylinder 19 is cut awayon opposite sides, as at 23, leaving two oppositely disposed ner.

supporting strips or columns 25. By this means, the cylinder is leftopen over about five-sixths of its circumference and to the depthindicated in dotted lines by the numeral 23. A slot 22 is formed in thelower part of the cylinder 19 and is provided at spaced intervals alongone side with offset horizontal portions or notches 18. This slot actsas a guide for the lug or screw 17. On the outer surface of the cylinder15 are spaced abutments 24, fixed to the side of the cylinder by anyordinary means as by soldering. Surrounding the outer cylinder andextending between the abutments 24 and the cap 21 is a coil spring 27.This spring is under compression and always exerts a lifting force onthe cap 21 and its attached inner cylinder 19. By this construction itmay be readily seen that the device may be held in closed position asillustrated in Figure 3, or by rotating the cap and inner cylinderslightly, the lug 17 may be freed from the upper notch in the slot 22and the spring allowed to lift the cap 21 and inner cylinder 19 to theraised or open position; I have shown the slot 22 as provided withnotches 18 so that the extent of the opening under the cap 21 can bevaried, and while I have shown three of these, the exact number isimmaterial.

As shown in Figure 2, the outlet conduit comprises an inner cylindricalportion 31 fitting in a correspondingly shaped opening '32 in thecrankcase and fixed there in any ordinary man- Immediately above thisportion 31 are shown bafile plates '33, arranged in an overlappingmanner in the intermediate portion 11, as

.portion 34, the section 11 of the outlet conduit is formed with adownwardly extending cylindrical opening 35 and fixed in this opening,as by welding orotherwise, is a tube 36 which is shown as extending downbelow the dustpan 40. The lower end of this tube is shown as sheared atan angle, as indicated at 37. The provision of this rearwardly fixedangled end on the tube 36 causes the, air currents resulting from themotion of the car to produce a slight suction or aspirating effect onthe tube, this action aiding the movement of the current of airthroughthecrankcase.

The device operates in the following manner:

With the engine running, the air pressure within the hood is increased,either by the fan or by forward movementfof the car, or both, and air isforced into the crankcase. The air inlets are shown as'on the left handside of the engine, in which case, as the crankshaft rotates clockwise,as viewed from thefront, circulation of the air is aided by itsrotation, as indicated by the arrows in Figure 2; Small particles of oilthat may be picked up by the current of air strike against the baflleplates 33 and drain back into the crankcase.

During cold weather, the combustion chamber gases which escape betweenthe piston and cylinder wall will condense more quickly than in warmweather, as the crank case and its associated parts stay colder. Hence,a greater current of air is required in cold weather than in warmweather. To make allowance for different temperatures, the effectiveextent of the inlet openings may be varied by fixing the lug 17 in anyone of the notches 18.

What I claim is:

1. A method of ventilating an automobile crankcase which consists in sorestricting and directing egress of air from a hood compartmentcontaining a radiator that the air entering thru the radiator into thehood will be therein maintained at higher than atmospheric pressure, andso directing the air from said hood as to force a current of air into acrank case.

A method of ventilating as defined in claim 1 in which the air sodirected is delivered from said crankcase through a tube terminatingoutside said hood in partially or completely closing the hoodcompartment so that the air entering the crankcase an air inlet openingwithin the hood compartment and an air outlet opening outside of saidcompartment, using the constant difierence in pressure for maintaining aconstant flow of air thru said openings.

3. In an automotive vehicle including an internal combustion engine anda closed hood, an inlet to the engine crankcase within the hood, meansfor adjusting the capacity of said inlet, and an outlet in the crankcaseextending to a point outside of the hood.

4. In an automotive vehicle including an internal combustion engine anda closed hood, an adjustable inlet inthe crankcase within the hoodcomprising a fixed member having an opening therein, a movable membersupported on said fixed member and adjustable to vary the capacity ofsaid opening, and an outlet in the crankcase extending to a pointoutside of the hood. 7

5. The combination in an automobile of a fclosedhood, as described, aninternal combustion engine disposed therein, said engine having acrankcase provided with an air inlet communicatingrwith the interior ofthe hood and an outlet communicating with atmosphere outside of 'thehood, said outlet comprising a conduit having an inte'riorly bafiiedportion rising from the crankcase and a portion communicating with thebaflied portion extending in a different direction and terminatingoutside of the hood.

WALTER A. GEISE.

